Protein-based hemostatic materials such as collagen and gelatin are commercially available in solid sponge, fibrillar and loose or unpacked powder form for use in surgical procedures. Mixing of the loose or unpacked powder with a fluid such as saline or thrombin may form a paste or slurry that is useful as a hemostatic composition for use in cases of diffuse bleeding, particularly from uneven surfaces or hard to reach areas, depending on mixing conditions and relative ratios of the materials.
Conventional slurries are prepared at the point of use by mechanical agitation and mixing of loose powder and liquid to provide uniformity of the composition. Mixing of the powder and fluid may be conducted in a container, such as a beaker. Such mixing requires transfer of the powder from its original container to the beaker, addition of the fluid to the beaker containing the powder, and then kneading of the mixture to form the paste. Only after the paste is thus formed may the paste be placed into a delivery means or applicator, e.g. a syringe, and applied to the wound. Alternately, attempts have been made to preload one syringe (Syringe I) with loose gelatin powder, and a second syringe (Syringe II) with liquid. When it is time to make a paste, Syringes I and II are connected via a luer lock and the solution in Syringe II is pushed into Syringe I. By attempting to pass the solution and powder repeatedly back and forth between Syringes I and II, a homogeneous paste may or may not be formed. Often in a surgical situation, a hemostatic paste with optimal powder:liquid ratio cannot be obtained due to insufficient mixing of the powder and the liquid in a syringe. When the powder is first mixed with a liquid, the powder hydrates rapidly to form a gel, thus blocking any further penetration of liquid into the mass of powder. Therefore, a homogeneous paste may not be achieved. Even if such methods of mixing are successful in forming a paste, the time and mechanical effort required to form the paste are undesirable or even unacceptable.
Such mixing procedures and manipulations are time consuming and potentially may compromise the sterility of the hemostatic paste. It would be desirable if a hemostatic composition could be provided which would eliminate the need for such undesirable mixing conditions. The present inventions provide a plurality of packed particles and compositions that more readily absorb aqueous liquids, such that undesirable mixing requirements as noted above are not required in order to form flowable hemostatic slurries, and/or that more readily absorb physiological fluids when placed at a site in the body of a mammal requiring hemostasis.